Graphite Terminology

Graphite uses many terms that can have ambiguous meaning. The following definitions are what these terms mean in the context of Graphite.

datapoint

A value stored at a timestamp bucket. If no value is recorded at a particular timestamp bucket in a series, the value will be None (null).

function

A time-series function which transforms, combines, or performs computations on one or more series. See Functions

metric

See series

metric series

See series

precision

See resolution

resolution

The number of seconds per datapoint in a series. Series are created with a resolution which determines how often a datapoint may be stored. This resolution is represented as the number of seconds in time that each datapoint covers. A series which stores one datapoint per minute has a resolution of 60 seconds. Similarly, a series which stores one datapoint per second has a resolution of 1 second.

retention

The number of datapoints retained in a series. Alternatively: The length of time datapoints are stored in a series.

series

A named set of datapoints. A series is identified by a unique name, which is composed of elements separated by periods (.) which are used to display the collection of series into a hierarchical tree. A series storing system load average on a server called apache02 in datacenter metro_east might be named as metro_east.servers.apache02.system.load_average

series list

A series name or wildcard which matches one or more series. Series lists are received by functions as a list of matching series. From a user perspective, a series list is merely the name of a metric. For example, each of these would be considered a single series list:

• metro_east.servers.apache02.system.load_average.1_min,
• metro_east.servers.apache0{1,2,3}.system.load_average.1_min
• metro_east.servers.apache01.system.load_average.*

target

A source of data used as input for a Graph. A target can be a single metric name, a metric wildcard, or either of these enclosed within one or more functions

timestamp

A point in time in which values can be associated. Time in Graphite is represented as epoch time with a maximum resolution of 1-second.

timestamp bucket

A timestamp after rounding down to the nearest multiple of a series’s resolution.

value

A numeric or null value. Values are stored as double-precision floats. Values are parsed using the python float() constructor and can also be None (null). The range and precision of values is system dependent and can be found by executing (with Python 2.6 or later):: python -c ‘import sys; print sys.float_info’